Although there may be many applications for such low pressure pulsing apparatus, an identified application is a reverse pulse mechanism for an industrial filter device. Such filter devices commonly have a housing divided into inlet and clean air chambers. The housing is divided with a partition having a plurality of apertures. A sock or bag of suitable fabric, often on a wire frame, is ordinarily suspended from each aperture. A suitable pump or blower causes air flow through the bags so that undesired particulate matter is filtered from the air. The particulate matter collects on the outer surface of the bags. Cleaning of the bags is accomplished by directing brief jets of air into the bags to reverse the air flow through the bags thereby subjecting them to a minor physical shaking and causing collected particulate matter to break away. The particulate matter falls to the bottom of the inlet chamber for removal either intermittently or continuously through a rotary air lock or other device.
Present devices are unable to release a high volume of low pressure air rapidly and, therefore, utilize a single high pressure chamber to release bursts of high pressure air into selected bags or filters at periodic intervals. Present systems commonly require a large quantity of valves and considerable plumbing and actuating mechanisms for the various valves.
U.S. Pat. Nos. 3,417,776 and 3,525,358 show different apparatus wherein relief valves release the pressure created by an explosion to protect a vessel from exploding. Each valve is essentially a spherical ball retained in a housing. The ball is forced into a sealing location by a slight external overpressure. Ordinarily, a plurality of such valves are fastened to the vessel. On explosion, each ball is forced into the housing and away from the sealing location thereby opening the port to the container and exposing a relatively large opening. These explosive relief valves require an overpressure from outside the container to hold the ball in a sealing position. During the explosion, the valves operate to release pressure from the ordinarily sealed port.
Known art does not include a valve which can rapidly release a large volume of low pressure gas from a container into, for example, an industrial air filtration machine.